Process for forming a composite structure of thermoplastic polymer and sheet molding compound

ABSTRACT

A process for making a rigid composite structure with a thermoplastic polymer surface by: 
     a. thermoforming a thermoplastic polymeric sheet into a three dimensional structure; the sheet has a primary glass transition temperature that is at least 10° C. greater than the molding temperature of step c. below; 
     b. placing the thermoformed structure and a charge of sheet molding compound (SMC) in a mold and 
     c. heating the charge and thermoformed structure under pressure in the mold to cure the SMC and to adhere the SMC to the thermoformed structure, where the molding temperature is at least 10° C. below the primary glass transition temperature of the thermoplastic polymeric sheet; 
     the resulting composite structure which can be finished with a paint or a layer of clear coat and color coat also is part of the invention.

BACKGROUND OF THE INVENTION

This invention is related to a process for forming a composite structureof sheet molding compound (SMC) and to the resulting compositestructure.

SMC, which is a composition of reinforced thermosetting polymericmaterial such as cured polyester resin reinforced with fiber glass, iswidely used for many parts used in trucks, buses, automobiles,appliances, business equipment, recreational vehicles and recreationalequipment such as water skis and the like. In the field of construction,SMC has been molded into such items as bathtubs, shower stalls, vanitiesand residential doors. In automobiles, SMC parts are used to replacesheet metal parts such as fenders, doors, hoods, and roofs. In somecases, the entire exterior of the auto has been made from SMC. Some ofthe advantages of SMC over metal parts are that SMC is free fromcorrosion and rapid deterioration from weathering which has always beena serious problem with metals; SMC parts are more resistant to dentingthan metals and SMC can be economically molded into intricate partswhich can not be done with metals.

After molding SMC into a part, the surface of the SMC is porous, roughand often has other imperfections and in general is not a smooth shiningclass A surface that can be finished readily or painted. To obtain asmooth paintable surface of high quality, the surface of the part isusually cleaned and primed with an appropriate primer and then paintedor a topcoating material applied such as a polyester gel coat. Anin-mold coating process can also be used as shown in Masuda et al U.S.Pat. No. 4,557,889 issued Dec. 10, 1985 in which a coating is sprayedinto a mold before the SMC part is formed. In the molding process, thecoating is adhered to the surface of the part. Paint injection moldingalso can be used in which paint is injected under pressure into the moldcontaining SMC to decorate the SMC part that is formed. To reduce costand improve efficiency, it would be desirable to eliminate any extrasteps as shown above in the above conventional processes used forfinishing SMC parts.

Conley et al U.S. Pat. No. 3,679,510 issued July 25, 1972, shows thelamination of a relatively thick thermoplastic sheet with a polyvinylfluoride outer surface to a glass fiber reinforced polyester resin sheet(SMC) to form a laminate. Such laminates having a major portion of athermoplastic sheet have a low modulus and are not useful for manyautomotive and truck parts that require high modulus materials forrigidity and thermal stability such as auto and truck hoods. When anattempt was made to reduce the thickness of the thermoplastic layer withthe materials taught by Conley et al, the imperfections from thefiberglass in the SMC layer show through and one cannot form a part thatis acceptable for automotive or truck use.

It would be desirable to form SMC parts that are relatively rigid, havea smooth surface that is free from surface imperfections of the SMCsubstrate and requires essentially no surface preparation prior topainting. Also, it would be desirable to form parts that have a highquality durable and weatherable finish that have the desired color thatmatches other painted parts of an auto or truck and that can be used inassembly without additional preparation. The novel process of thisinvention provides the above; it forms SMC parts that are relativelyrigid and have a class A surface that can be readily painted or forms arelatively rigid SMC part that has a high quality colored surface orprefinished surface finished with a layer or layers of paint thatmatches adjacent painted or colored surfaces of metallic or plasticparts and can be used directly for auto or truck assembly.

SUMMARY OF THE INVENTION

A process for making a rigid composite structure with a thermoplasticpolymer surface using the following steps:

a. a thermoplastic polymeric sheet is thermoformed into a threedimensional structure; the thermoplastic polymeric sheet has a primaryglass transition temperature that is at least 10° C. greater than themolding temperature of step e. below;

b. a mold having an upper die and lower die with opposing moldingsurfaces cooperating to define a mold cavity with one of the dies havinga shape corresponding to the three dimensional thermoformed structure isopened;

c. the thermoformed structure prepared in step a. above and a charge ofsheet molding compound (SMC) are placed on the molding surface of one ofthe dies;

d. the mold is closed so that the dies compress the charge causing it tofill the mold cavity;

e. the charge and thermoformed structure are molded by heat and pressureto cure the SMC and to adhere the SMC to the thermoformed structure, amolding temperature of at least 10° C. below the primary glasstransition temperature of the thermoplastic polymeric sheet is used,preferably a temperature of about 135°-160° C. and a pressure of about3-15 MPa are used; and

f. the dies are opened and the resulting rigid composite structurehaving a thermoplastic polymer surface composed of the thermoformedstructure firmly adhered to the SMC is removed.

Another part of this invention is the rigid composite structure that hasa flexible thermoformed sheet of a thermoplastic polymeric materialhaving a glass transition temperature of at least 145° C. and is atleast 10° C. above the aforementioned molding temperature that is bondedto a thick rigid layer of SMC composed o a thermosetting polymeric resinreinforced with materials such as filler pigments, fiberglass and thelike as is the finished composite structure having an outer layer of aglossy clear thermoplastic finish that is firmly bonded to a layer of athermoplastic pigment containing paint that is firmly bonded to a thinsize layer of a thermoplastic polymer that is firmly bonded to theflexible thermoformable sheet of the composite structure. Another aspectof this invention is a flexible laminate of a glossy clear layer, apigment containing paint layer and a thin size layer bonded to theflexible thermoformable sheet.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a cross section of the composite structure of athermoformed thermoplastic sheet 2 bonded to a thick rigid layer of SMC1.

FIG. 2 shows a cross section of the composite structure having a clearlayer 5, a pigmented layer 4, a size layer or layers 3, a thermoformedthermoplastic polymeric sheet 2, and a thick rigid layer 1 of SMC.

FIG. 3 shows a cross section of the thermoformable laminate or facesheet of a clear layer 5, a pigmented layer 4, a size layer or layers 3,a thermoformable thermoplastic polymeric sheet 2.

FIG. 4 shows roller coating of paint onto a polyester film and theformation of the thermoformable laminate or face sheet.

FIG. 5 shows the process for making the composite structure from theface sheet.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a cross section of the composite structure of athermoformed thermoplastic sheet 2 bonded to a thick rigid layer 1 ofSMC of a thermosetting polymeric resin reinforced with filler pigmentand glass fibers. Preferably, the thermoformable thermoplastic sheet isabout 125-1000 microns thick and the SMC layer is about 1500-7500microns thick. A second layer of the thermoplastic sheet 2 can be bondedto the bottom side of the SMC layer to form a reinforced structure.

FIG. 2 shows a cross section of the composite structure having a clearcoat/color coat or pigmented paint layer. Layer 5 which is the exteriorlayer of the composite is a thermoplastic clear coating that has anglossy finish. If the composite is to be used for autos and trucks, thecoating must have excellent weatherability, scratch and mar resistanceand good gloss retention on weathering. Layer 5 is firmly adhered topaint layer 4 which is a pigmented paint and if used for autos andtrucks, it also must be of automotive quality that withstands weatheringand does not crack and fade. The combination of layers 4 and 5 providethe composite structure with a high quality finish that has theaforementioned properties required for automotive uses.

Layer 3 of FIG. 2 is a thin layer of a thermoplastic size that providesintercoat adhesion of the pigmented paint layer 4 to layer 2 which is athermoplastic polymeric sheet. Layer 1 is a relatively thick rigid layerof SMC of a polyester resin polymerized with monomers such as styreneand contains filler pigments and is reinforced with fiber glass.Preferably, a weight ratio of about 1:1:1 of polyester resin to fillerpigments to fiber glass is used.

Preferably, the composite structure has the following thickness for eachlayer:

1. a 15-125 micron thick layer of the glossy clear thermoplastic finishthat is bonded firmly to

2. a 10-75 micron thick layer of the thermoplastic pigment containingpaint that is firmly bonded to

3. a 1-20 micron thick layer or layers of a thermoplastic size that isfirmly bonded to

4. a 125-1000 micron thick layer of a flexible sheet of a thermoplasticpolymeric material that is bonded to

5. a 1500-7500 micron thick rigid layer of SMC.

In the formation of the composite structure, a thermoformable laminateor face sheet is first formed. FIG. 3 shows a cross section of the facesheet. The face sheet is composed of layers 2-5 of the above compositestructure and each of these layers has the same thickness as set forthabove for the composite structure.

FIG. 4 shows a process for making the laminate or face sheet. A flexiblepolymeric carrier sheet 6, preferably a polyester film, typically a"Mylar" 200A polyethylene terephthalate film about 50 microns thick, isfed through a 3 roll roller coater 7 containing a clear coatingcomposition 8 and by reverse roller coating, about a 15-125 micron thickclear coating (dry basis) is applied. Coating line speeds of about 5-25meters/minute are used. The coated film is then passed through the oven9, preferably having multiple heating zones. Typically, three heatingzones are used in the oven. The first zone is at about 125° C. and thelast zone is at about 200° C. A solvent incinerator 10 is used toincinerate solvent fumes from the coating composition. The coated filmis then wound into roll 11. The roller coater 7 is filled with apigmented coating composition instead of the clear composition and theprocess is repeated to apply about 10-75 micron thick coating (drybasis) of the pigmented coating or color coat over the clear coat layeron the film to form a polyester film having a clear coat layer and acolor coat layer. The resulting coated polyester film 11 is then coatedusing the same process with a 1-25 micron thick layer (dry basis) of asize layer of a thermoplastic polymer such as a polyurethane.

The resulting coated polyester film is then laminated to a thermoplasticpolymeric sheet about 125-1000 microns in thickness. The roll of coatedpolyester film 11 and a roll of the thermoplastic polymeric sheet arefed at a line speed of about 5-20 meters/ minute through guide rollers13 and then through two heated nip rollers 14 that are at a temperatureof about 200° C. and a pressure of about 65 to 350 kg/linear cm is usedto form a laminate. The resulting laminate is passed around chill roll15 and the laminate or face sheet 16 which is thermoformable and iswound into a roll.

FIG. 5 shows the removal of the polyester film from the face sheet 16which is wound onto a roll 17. A section of the resulting face sheet isthen thermoformed into a shaped structure by placing it in a vacuumformer 18 containing heating lamps 19 and the face sheet is heated toabout 190°-235° C. The sheet is then thermoformed by pulling a vacuumand using a pressure assist of up to 3 atmospheres. Usually, about 1-3atmospheres of pressure are used. The resulting thermoformed structure20 having a painted surface can be used in a molding process with SMC toform a part such as an auto or truck part. The shaped structure 20 ispositioned in a conventional compression molding machine 21. A thicklayer of green or uncured SMC 1 is positioned on the bottom die of themold. Preferably, the SMC charge covers about 40-80% of the moldingsurface of the die. The mold is closed and the composite is heatedpreferably to about 140°-160° C. and molded under a pressure of about 3-15 MPa. The SMC which has been cured in the process forms the backinglayer of the resulting composite and is about 1500-7500 microns inthickness. The resulting composite or part 23 is useful for autos andtrucks and has a surface that is smooth and glossy, has an excellentdistinctness of image and good color uniformity and in general meets allthe requirements of an automotive finish.

The glossy clear finish and the paint layer provide the compositestructure with an exterior decorative finish. To be acceptable forautomotive and truck use, the finish must have the following properties:a gloss measured at 20° of at least 80 and measured at 60° of at least90, a distinctness of image (DOI) of at least 80, must have gasoline,abrasion, mar and acid resistance, and excellent weatherabilityincluding good gloss retention.

The following is a description of the test methods used to determine theabove properties. Certain test methods identified below are publiclyavailable standard industry specifications and test methods which areincorporated herein by this reference.

Gloss is measured by specular reflectance of a beam of light at anglesof 20° and 60°. Specular reflectance is measured before the finishedpainted surface is buffed and waxed. A Byk-Mallinckrodt "multigloss" or"single gloss" gloss meters are used for measuring specular gloss of thefinish. These gloss meters give values equivalent to those obtained fromASTM Method D-523-67. The preferred test method is described in GM TestSpecification TM-204-A.

Distinctness-of-Image (DOI) is a measurement of the clarity of an imagereflected by the finish. DOI is measured from the angle of reflection ofa light beam from a spherical surface. DOI is measured by the HunterlabModel No. D47R-6F Doigon Gloss Meter. A test panel is placed on theinstrument sensor and the sharpness of the reflected image is measured.Details of the DOI test procedure are described in GM Test SpecificationTM-204-M.

Gasoline Resistance requires that there is no color change, degradation,tackiness, marring or loss of paint adhesion on plastic parts after afinished part is immersed for ten seconds, ten times, in a specifiedreference fuel with a 20 second dry off period between each immersion.Immediately after the tenth immersion, the painted surface is checkedand must pass Thumbnail Hardness according to GM Test Specification TM55-6.

Cleanability is tested according to GM Test Specification TM 31-11 inwhich the painted plastic part is subjected to ten rubs with cheeseclothsaturated with 9981062 Naphtha or currently used and approved cleaningsolvents. There should be no evidence of staining, discoloration, orsoftening of the painted surface and no evidence of color transfer fromthe painted surface to the cloth. One rub consists of one forward andbackward motion.

The Acid Spotting Resistance Test requires the painted part to withstandexposure to 0.1 N sulfuric acid for 16 hours without any evidence ofstaining, discoloration, or softening of the paint.

Hardness is measured by a standard Knoop Hardness Test.

Chip resistance is determined by a Gravelometer Test described in SAEJ-400. The painted part as received and after 3 and 6 months Floridaexposure, described below, is tested at -23° C. and must have a minimumrating of 8 as determined by F. B. Gravelometer Rating Chart.

Impact strength of a painted part is tested at room temperature by theGardener Test and by the Rosand Test at -29° C.

Paint Adhesion of a painted part is determined by a standard TapeAdhesion Test described in GM Test Specification TM 55-3. According tothis test, a tape is pressed down over an X-shaped cut in the paint coatand the tape is then removed to test the amount of peeling. The testrequires a minimum of 99% of the paint remaining in the tape test area.

Resistance to Water and Humidity Exposure is measured by several tests.In one test, the finished part is exposed to 96 hours of humidityexposure at 100% relative humidity and 38° C. in a humidity cabinetdefined in GM test specification TM 55-3, and a two-hour water immersiontest at 38° C. according to GM test specification TM 55-12. Theresulting paint panel should show no evidence of blistering whenexamined one minute after removal from the test cabinet and shallwithstand the Paint Adhesion Test described above. The Paint AdhesionTest is performed within one minute after removal from either testcabinet. In a second test, the painted panel should withstand 15 cyclesof the Moisture-Cold Cycle Test defined in GM test specification TM45-61A, without any visible signs of cracking or blistering. After 15cycles, the paint panel is exposed to 96 hours of the humidity exposuredescribed above, followed by the Paint Adhesion Test also describedabove. The panel is expected to pass both tests. The Paint Adhesion Testis performed within one minute after removal from the humidityenvironment. One cycle consists of 24 hours and 100% relative humidityat 38° C., 20 hours at -23° C., and four hours at room temperature.

For outdoor weatherability, painted panels are exposed for up to 3 yearsin Florida facing south in a black box positioned 5° from thehorizontal. The painted panels should retain 40% of their original glossand there should be no blistering or fading of the paint.

The finish must be sufficiently flexible at thermoforming temperaturesand must have sufficient durability to withstand thermoforming andcompression molding process without embritteling, cracking or otherwisedegrading the finish. The finish must retain its gloss and otherappearance properties after processing.

In the event the composite is used for other purposes than exteriorautomotive and truck parts, the requirements of the finish are differentand usually less than indicated above and the clear finish may beeliminated and only the pigmented or colored finish used. For example,bathtubs and shower stalls would not require a clear and pigmentedfinish with exterior durability and appearance as required for anautomotive part and only a pigmented finish may be used.

Colored pigments or dyes can be incorporated into the thermoplasticpolymeric sheet by using conventional techniques and a compositestructure can be formed with a colored surface without the use of afinish. A composite structure with a colored thermoplastic polymericsheet may be adequate for many uses such as interior parts forautomobiles and trucks, the back of a composite structure with a paintedor finished surface such as the inside of a hood that has a paintedsurface, or for shower stalls or bathtubs.

The glossy clear finish used for an exterior automotive or truck part isformed from a clear coating composition. The composition contains about15-80% by weight film forming binder and correspondingly, about 85-20%by weight of a liquid carrier. The composition may have a solventcarrier or an aqueous carrier and the binder of the composition may bein solution or in dispersion form. The binder basically is thermoplasticand needs to withstand the thermoforming and molding process for makinga part. Both the clear layer and the pigmented or colored layer of thecomposite structure must be able to withstand an elongation of about40-150% at a film thickness of about 10-50 microns and thermoforming

Thermoplastic fluorinated polymers such as polyvinyl fluoride (PVF),polyvinylidene fluoride (PVDF) and copolymers and terpolymers thereofalso can be used for the clear coating composition. A blend of anacrylic resin and a fluorinated polymer also can be used.

The blend contains about 50-80% by weight of PVDF and correspondingly20-50% by weight of a polyalkyl methacrylate. Generally, a highmolecular weight (MW) PVDF resin is used having a weight average MWweight of about 200,000-600,000 and a relatively high MW polymethylmethacrylate or polyethyl methacrylate having a weight average MW ofabout 50,000-400,000.

To improve weatherability of the clear coat about 0.1-5%, by weight,based on the weight of the binder, of an ultraviolet light stabilizer orscreeners or a combination of ultraviolet light stabilizers andscreeners can be added to the clear coating composition. Typicallyuseful ultra-violet light stabilizers and screeners are as follows:

Benzophenones such as hydroxy dodecyloxy benzophenone,2,4-dihydroxybenzophenone, hydroxybenzophenones containing sulfonicgroups and the like.

Triazoles such as 2-phenyl-4-(2',2'-dihydryoxylbenzoyl)-triazoles,substituted benzotriazoles such as hydroxy-phenyltriazoles and the like.

Triazines such as 3,5-dialkyl-4-hydroxyphenyl derivatives of triazine,sulfur containing derivatives of dialyl-4-hydroxy phenyl triazines,hydroxy phenyl-1,3,5-triazine and the like.

Benzoates such as dibenzoate of diphenylol propane, tertiary butylbenzoate of diphenylol propane and the like.

Other ultraviolet light stabilizers that can be used include lower alkylthiomethylene containing phenols, substituted benzenes such as1,3-bis-(2,-hydroxybenzoyl)benzene, metal derivatives of3,5-di-t-butyl-4-hydroxy phenyl propionic acid, asymmetrical oxalicacid, diarylamides, alkylhydroxy-phenyl-thioalkanoic acid ester and thelike.

The clear coat can also contain transparent pigments, i.e., pigmentshaving the same or similar refractive index as the binder of the clearcoat and are of a small particle size of about 0.015-50 microns. Typicalpigments that can be used in the clear coat in a pigment to binderweight ratio of about 1/1000 to 10/1000 are inorganic siliceouspigments, such as silica pigments. These pigments have a refractiveindex of about 1.4-1.6.

The color coating composition used herein has as the binder any of theaforementioned binders used in the clear coating composition and also itmay be advantageous to use ultraviolet stabilizers in the composition.The composition does contain pigments in a pigment to binder weightratio of about 1/100 to 100/100.

Any of the conventional pigments used in coating compositions can beutilized such as the following: metallic oxides, such as titaniumdioxide, zinc oxide, iron oxide and the like, metal hydroxide, metalflakes such as aluminum flake, pearlescent pigments, chromates, such aslead chromate, sulfides, sulfates, carbonates, carbon black, silica,talc, china clay, phthalocyanine blues and greens, organo reds, organomaroons and other organic pigments and dyes.

The pigments are formulated into a mill base by mixing the pigments witha dispersing resin which may be the same as the binder of thecomposition or may be another compatible dispersing resin or agent. Thepigment dispersion is formed by conventional means such a sand grinding,ball milling, attritor grinding, two roll milling. The mill base is thenblended with the binder of the composition to form the coatingcomposition.

Often it is convenient or necessary to apply a thin size layer orseveral size layers to the pigmented layer to improve or enhanceadhesion to the thermoplastic polymeric material. Typical polymericmaterials useful for the size layer are polyalkyl acrylates, polyalkylmethacrylates, vinyl chloride polymers, polyurethanes, polyimides, andmixtures of the above.

The thermoplastic polymeric sheet used in the composite hides anyimperfections in the surface of the SMC substrate. The thermoplasticpolymeric sheet must be of a sufficient thickness, preferably 125-1000microns thick, and have a glass transition temperature of at least 10°C. above the molding temperature of the sheet to the SMC to accomplishthe above. By not excessively softening the thermoplastic polymericsheet during molding, any surface defects of the SMC substrate usuallycaused by glass fibers in the SMC will not show through to the surfaceof the resulting composite structure formed by the process of thisinvention. This will allow higher levels of glass fiber and filler to beused in the SMC than is conventionally used.

Preferably, a thermoplastic polymeric material having a primary glasstransition temperature of at least 145° C. is used. Preferably, apolyarylate is used. The polyarylate optionally can contain at least oneolefin polymer. The polyarylate is the reaction product of at least onedihydric phenol and at least one dicarboxylic acid. Any of the wellknown dihydric alcohols and dicarboxylic acids can be used to form thepolyarylate.

One prefered polyarylate is the polymerization product of2,2-bis(4-hydroxyphenyl) propane and an aromatic dicarboxylic acid fromthe group of isophthalic acid, terephthalic acid or any mixturesthereof.

One useful olefin polymer that can be blended with the polyarylate hasepoxide functionality and is the polymerization product of the followingmonomers:

(a) about 0.5-15% by weight, based on the weight of the olefin polymer,of ##STR1## where R is H or alkyl group having 1-6 carbon atoms, (b)about 45-99% by weight, based on the weight of the olefin polymer, ofCH₂ ═CHR where R is H or lower alkyl group, and

(c) about 0.1-40% by weight, based on the weight of the olefin polymer,of CH₂ ═C(R¹)COOR² where R is H or lower alkyl and R² is an alkyl grouphaving 1-8 carbon atoms.

One particularly useful olefin polymer for the polyarylate is thepolymerization product of glycidyl methacrylate, ethylene and butylacrylate.

The polyarylate can contain up to 15% by weight of a copolymer of atleast one of styrene and alpha methyl styrene and at least one ofacrylonitrile and methacrylonitrile. Preferably, a copolymer of styreneand acrylonitrile is used.

One preferred thermoplastic polymer sheet used to form the compositecontains about

(a) 85 to 98% by weight of a polyarylate of the polymerization productof 2,2-bis(4-hydroxyphenol) propane terephthalic acid and isophthalicacid,

(b) 2-15% by weight of an olefin polymer containing epoxidefunctionality of the polymerization product of about

(1) 0.5-15% by weight, based on the weight of the olefin polymer ofglycidyl methacrylate,

(2) 45-99% by weight, based on the weight of the olefin polymer ofethylene, and

(3) 0.1-40% by weight, based on the weight of the olefin polymer, ofbutyl acrylate.

Another preferred thermoplastic polymeric sheet contains about

(a) 84 to 98.7% by weight of a polyarylate of the polymerization productof 2,2-bis(4-hydroxyphenol) propane terephthalic acid and isophthalicacid,

(b) 1-22% by weight of an olefin polymer containing epoxidefunctionality of the polymerization product of about

(1) 0.5-15% by weight, based on the weight of the olefin polymer ofglycidyl methacrylate,

(2) 45-99% by weight, based on the weight of the olefin polymer ofethylene, and

(3) 0.1-40% by weight, based on the weight of the olefin polymer, ofbutyl acrylate and

(c) 0.3-15% by weight of a copolymer of styrene and acrylonitrile.

Other thermoplastic polymeric materials can be used such as a polyethersulfanone or polyamides modified with a polyarylate or with poly(2,6dimethyl phenylene oxide). Typically useful polyamide are Nylon 66 whichis polyhexamethylene adipamide and Nylon 612. However, modifiedpolyamides and polyether sulfanones require a size layer be placedbetween the polyamide or polyether sulfanone and the SMC substrate toachieve the adhesion level desired. A polyurethane,acrylonitrile/butadiene/styrene terpolymer (ABS), styrene/acrylonitrilecopolymer (SAN) or polystyrene can be used as the size layer.

The SMC layer of the composite typically is a polyester resinpolymerized with monomers, filler pigment and glass fibers. Generally,the SMC contains about 30% by weight of glass fibers but SMC sheetscontaining 35% and above of glass fiber also can be used. The polyesterresin is an acid terminated polyester of an alkylene glycol and analiphatic and an aromatic dianhydride or acid and the polymerizedmonomers of styrene or alph-methyl styrene. In one preferred SMC, thepolyester resin is the esterification product propylene glycolisophthalic acid and maleic anhydride and the monomer is styrene and thepolyester is reacted with magnesium oxide, magnesium hydroxide ormagnesium carbonate and the filler pigment is calcium carbonate. Also,the SMC can contain up to 15% by weight of a low profile additive of ahigh molecular weight thermoplastic resin.

Instead of the SMC, a thermally curable polymeric material reinforcedwith a material such as fiberglass and that can be processed byinjection molding can be used. Common materials of this type are known aPIM, pressure injection molded material or RRIM, reinforced reactioninjection molding material. Typically useful materials of this type arepolyurethanes, polyureas, polyamides, polyesters or blands thereofcontaining fiberglass and filler pigments. In utilizing such materialsto form a part, the thermoformed face sheet described herein is placedin an injection molding machine and the thermally curable material isinjected in back of the face sheet and cured and a part is formed.

The composite structure of this invention provides many advantages overprior art SMC structures. The composite structure has a class A surfaceand can be readily finished with paint or with a gel coat withoutsurface preparation such as cleaning and priming thereby saving costs inthe finishing process. To reduce cycle time, the composite can beremoved from the mold before it is fully cured and then afterward fullycured by thermal or radiation curing. An additional finish, for exampleto improve mar resistance, may be applied after the part is removed orin the coating of the face sheet which is crosslinked by this furthercuring.

The composite structure can be prepared with a colored thermoplasticlayer or can be formed with a colored paint layer or with a clear coatand pigmented paint layer and can be used for auto and truck partswithout additional painting. Outside of the automotive field, partsformed from the composite structure can be used for recreationalequipment such as snow mobiles, skis and the like, for appliances,business equipment, for building construction for items such asbathtubs, shower stalls, vanities, doors and the like.

The following Examples illustrate the invention. All parts andpercentages are on a weight basis unless otherwise indicated andmolecular weights are determined by gel permeation chromatography usingpolymethyl methacrylate as a standard.

The following abbreviations are used in the examples:

PVDF--polyvinylidene fluoride

PVF--polyvinyl fluoride

SMC--sheet molding compound

UV--ultraviolet light

BLO--butyrolactone

DIBK--diisobutyl ketone

ABS--acrylonitrile/butadiene/styrene terpolymer

EXAMPLE 1

A high gloss red laminated exterior automotive paint coat was formed onthe top surface of a 15.25 cm×25.4 cm SMC test plaque. The paint coatwas first coated onto a casting film comprising a 50 micron thick highgloss "Mylar" A200 polyester film. A clear coat, color coat, and sizecoat were coated onto the casting film in that order.

The clear coat was prepared from the following formulation:

    ______________________________________                                        Ingredient               Parts                                                ______________________________________                                        Cyclohexanone            15.47                                                BLO                      7.52                                                 DIBK                     21.66                                                Polyethyl methacrylate ("Elvacite" 2042)                                                               12.95                                                UV absorbers             1.10                                                 PVDF ("Kynar" 301F)      24.05                                                BLO                      17.25                                                Total                    100.00                                               ______________________________________                                    

The "Elvacite" acrylic resin was dissolved in the BLO, DIBK andcyclohexanone solvents, while mixing and under heat at approximately 54°C. The resulting mixture was allowed to cool overnight. The UV absorberswere then added to the mixture and the PVDF was dispersed in the resin.The remaining BLO solvent was added to dilute the final mixture. ThePVDF component was dispersed in the mixture and not dissolved. The driedclear coat contained approximately 65% PVDF and 35% acrylic resin, basedon the total PVDF and acrylic solids.

The clear coat was coated on the casting film in a dry film thickness of15 microns. The clear coat was applied by a reverse roll coater. Theclear coat was dried on the carrier sheet by passing it through amulti-zone impinging air drying oven having three heating zones spacedapart axially along the length of the carrier, with each drying zonehaving a progressively higher temperature. The clear-coated carrier waspassed through the heating zones at a line speed of 7.62 meters perminute and each heating zone was 12.2 meters long. Temperatures of thethree heating zones were: Zone 1: 127° C., Zone 2: 165° C., Zone 3: 200°C. Passing the clear coat through the three heating zones removedsubstantially all solvent gases from the clear coat to produce a dryclear coat of uniform film thickness.

A red color coat was next coated on the dried clear coat at a filmthickness of about 20 microns. The red color coat was formulated asfollows:

    ______________________________________                                        Ingredient               Parts                                                ______________________________________                                        Cyclohexanone            10.61                                                Polyethyl methacrylate ("Elvacite" 2042)                                                               2.99                                                 Dispersing agent (Solsperse 17,000)                                                                    0.10                                                 PVDF ("Kynar" 301F)      19.95                                                BLO                      4.02                                                 Solvent (N-methyl pyrrolidone)                                                                         8.45                                                 Red Dispersion           57.90                                                Total                    104.02                                               ______________________________________                                    

The red dispersion comprised several pigments including red pigmentdispersed in a vehicle of polyethyl methacrylate resin, "Elvacite" 2043,16% solids, and 84% cyclohexanone solvent. The red color coat wasprepared in a similar manner to the clear coat in that the acrylic resinwas first dissolved in the solvents at a temperature of about 55° C. Thedispersing agent and a portion of the red dispersion were added. Themixture was allowed to cool to room temperature and the PVDF componentwas dispersed using a high speed mixer. The remainder of the reddispersion was then added to the resulting mixture to produce a redcolor coat.

The binder of the color coat has approximately 65% PVDF andapproximately 35% acrylic resin, by weight of the total PVDF and acrylic(non-pigment) solids. The acrylic resin component contains polyethylmethacrylate, approximately 80% "Elvacite" 2043 and approximately 20%"Elvacite" 2042. The pigment was present in a ratio of three partspigment to ten parts resin binder, or approximately 23% of the totalsolids. The color coat was coated onto the dried clear coat and thenpassed through the three-stage oven described above and dried.

A size coat was next prepared for use with a polyarylate thermoplasticpolymeric sheet. The size coat formulation was as follows:

    ______________________________________                                        Ingredient               Parts                                                ______________________________________                                        Water based Polyurethane resin                                                                         53.07                                                ("Neo Rez" R-9314 made by Polyvinyl                                           Chemical Company)                                                             Water based Polyurethane resin                                                                         35.31                                                ("Neo Cryl" A-5144 made by Polyvinyl                                          Chemical Company)                                                             "Surfynol" 104H surfactant made by                                                                     0.27                                                 Air Products Company)                                                         Bubble Breaker 3056A made by Witco                                                                     0.05                                                 Chemical Company)                                                             "Triton" X-100 (nonionic surfactant                                                                    0.30                                                 made by Rohm and Hass)                                                        Isopropyl alcohol        0.97                                                 "Acrysol" TT-678 Thickener made by                                                                     0.24                                                 Rohm and Hass                                                                 Deionized water          8.91                                                 "Lo Vel" 27 silica flattening agent                                                                    0.88                                                 Total                    100.00                                               ______________________________________                                    

The size coat was then coated onto the dried color coat in a filmthickness of about 4 microns. The size coat was applied by a reverseroll coater and then dried in the same three-stage drying oven as theclear coat and the color coat. The resulting paint-coated casting filmwas transferred to a laminating operation as shown in FIG. 4, describedabove, where the paint coat was transferred from the casting film to a500 micron thick polyarylate facesheet made from Du Pont Bexloy® M401polyarylate resin. A temperature of 200° C. and a pressure of about 100kg/linear cm was used to form the laminate. The polyarylate resin has aglass transition temperature of about 175°-185° C. and is thepolymerization product of 2,2-bis-(4-hydroxyphenyl)propane and a 97/3mixture of isophthalic acid and terephthalic acid and contains 7.5% byweight of a terpolymer of ethylene/butyl acrylate/glycidyl methacrylate.The casting film was stripped away from the surface of the resultinglaminate, leaving a red paint coat with a high gloss surface on theexterior of the polyarylate facesheet.

The laminate was then thermoformed by heating the laminate to atemperature of about 210° C. After the sheet was heated to thistemperature, it was moved over a vacuum-former and a vacuum was drawnand a pressure of about 1 atmosphere was used to form the laminate intoa thermoformed structure of a 6"×10" test plaque.

The plaque was trimmed and then was inserted into a 15.25 cm×25.4 cmmold that was heated to 145° C. and placed in a 100 ton SMC press. Thered color coat/clear coat finish of the plaque was placed against a highquality polished class A surface mold face. 300 grams of green SMC (BuddCo. DSM 950) was added to the mold and the mold was closed for 3minutes. A temperature of 155° C. and a pressure of 10 MPa was used.

The DSM 950 SMC sheet has a specific gravity of 1.92, a flexuralstrength of about 160-185 MPa, a compressive strength of about 130-160MPa, a tensile strength of about 65-80 MPa and is believed to be apolyester of propylene glycol and maleic anhydride and isophthalic acid,containing calcium carbonate filler pigment and fiberglass.

The resulting decorated cured SMC test plaque had a total thickness of0.33 cm. The 20° gloss was 78 and the DOI was 83. The adhesion of thefinish to the Bexloy® M401 facesheet was excellent and the adhesion ofthe Bexloy® M401 facesheet to the SMC was excellent. The plaque wastested against the automotive specification and in general met thesespecifications and showed the above process can produce automotive gradefinished SMC parts.

EXAMPLE 2

A low gloss black laminated paint coat was formed on the top surface ofa 25.4 cm×45.7 cm SMC plaque. A clear coat consisting of particulatepolyvinyl fluoride dispersed in propylene carbonate solvent at 35%weight solids was substituted for the PVDF/acrylic clear system inExample 1 and was applied to a casting film described in Example 1 todry film thickness of 50 microns and cured using the same procedure asin Example 1.

A black color coat was next coated on the dried clear coat at a filmthickness of about 50 microns. The color coat formulation was asfollows:

    ______________________________________                                        Ingredient               Parts                                                ______________________________________                                        PVF dispersion (35% PVF in propylene                                                                   50.0                                                 carbonate solvent)                                                            Black pigment dispersion 50.0                                                 Total                    100.0                                                ______________________________________                                    

The black color coat has a pigment to binder weight ratio (P/B) of11.6/100 and a binder composition of PVF/MMA-MESO/acylic copolymerdispersant of 82/5/13. The black color coat was applied to the clearcoat on the casting film prepared above and dried using the process ofExample 1. The resulting color coat was treated with a conventionalcorona electrical discharge treatment and then a size layer of 4 micronsof the size coat of Example 1 was applied using the same procedure as inExample 1. The resulting paint-coated casting film was transferred to alaminating operation shown in FIG. 4 described above, where the paintcoat was transferred from the casting film to a 425 micron thickpolyarylate facesheet made from Du Pont Bexloy® M492 polyarylate resinhaving a glass transition temperature of about 150° C. A temperature ofabout 200° C. and a pressure of about 100 kg/linear cm were used for thenip rollers to form the laminate. The polyacrylate resin is thepolymerization product of 2,2-bis-(4-hydroxyphenyl)propane and a 97/3mixture of isophthalic acid and terephthalic acid and contains aterepolymer of ethylene/butyl acrylate/glycidyl methacrylate. Thecasting film was stripped away from the surface of the resultinglaminate, leaving a black paint coat with a low gloss surface on theexterior of the polyacrylate facesheet.

The laminate was then thermoformed by heating the laminate to atemperature of about 200° C. After the sheet was heated to thistemperature, it was moved over a vacuum-former and a vacuum was drawnand a pressure of about 1 atmosphere was used to form the laminate intothermoformed structure of a 25.4 cm×45.7 cm test plaque.

The plaque was trimmed and then was inserted into a 25.4 cm×45.7 cm moldthat was heated to 138° C. and placed in a 100 ton SMC press. The blackcolor coat/clear coat finish of the plaque was placed against a smoothdull surface mold face. 600 grams of green SMC (Budd Co. DSM 930) wasadded to the mold and the mold was closed for 3 minutes. A temperatureof 138° C. and a pressure of 8 MPa was used.

The DSM 930 SMC sheet has a specific gravity of 1.90, a flexuralstrength of about 160-185 MPa, a compressive strength of about 140-165MPa, a tensile strength of about 65-80 MPa and is believed to be apolyester of propylene glycol and maleic anhydride and isophthalic acid,containing calcium carbonate filler pigment and fiberglass.

The resulting decorated cured SMC test plaque had a total thickness of0.25 cm. and a low gloss suitable for automotive trim and under hoodparts. The adhesion of the finish to the Bexloy® M492 facesheet wasexcellent and the adhesion of the Bexloy® M492 facesheet to the SMC wasexcellent. The plaque was tested against the automotive specificationand in general met these specifications and showed the above process canproduce automotive grade finished SMC parts for trim and under hood use.

EXAMPLE 3

The product of Example 2 was made according to the process of Example 2except the 100 ton SMC press was equipped with a vacuum seal asdisclosed in U.S. Pat. No. 4,612,149 and evacuated before compressingthe green SMC and an additional second piece of uncoated Bexloy® M 492measuring 10"×18" was placed in a mold in contact with the green SMC onthe opposite side of the thermoformed plaque.

The plaque that was produced had the low gloss black finish on the topsurface and a layer of Bexloy® M 492 on the bottom. The bottom layer canbe used as a protective layer or as a substrate for further processingsuch as by painting.

EXAMPLE 4

The following series of polyarylate resins sheets having a glasstransition temperature of about 175°-185° C. were thermoformed and werelaminated to an SMC substrate compounded in an extruder with thefollowing compositions:

    ______________________________________                                        Polyarylate                                                                           %         I/T     Modifier                                                                              Rubber                                      Sheet   Polyarylate                                                                             Ratio   Resins  Tougheners                                  ______________________________________                                        A       87.5      97/3    5%   SAN  7.5  EBAGMA                               B       83.0      97/3    5%   SAN  12%  EBAGMA                               C       92.5      97/3    --        7.5  EBAGMA                               D       80.8      75/25   5%   SAN  11.7 EBAGMA                               E       83.3      75/25   7.4% SAN  9.3  TRX101                               F       100.0     97/3    --        --                                        G       100.0     50/50   --        --                                        ______________________________________                                    

Polyarylate--polymerization product of 2,2-bis-(4-hydroxyphenyl)propaneand mixture of isophthalic acid and terephthalic acid.

I/T--ratio of isophthalic acid and terephthalic acid used in thepolyarylate

SAN--styrene/acrylonitrile polymer

EBAGMA--ethylene/butyl acrylate/glycidyl methacrylate terpolymer

TRX101--functionalized polyethylene made by Du Pont

These sheets of polyarylate are used at several thickness between250-625 mils. Each sheet was thermoformed at about 190°-220° C. andinserted in the 25.4 cm×45.7 cm mold with the vacuum seal used inExample 3. The mold was heated to 160° C. and plaques of varyingthickness were formed by molding for 3 minutes. The resulting plaqueswere between about 1250-5000 microns in thickness and were made withBudd Co. DSM 944, DSM 930 and DSM 950. All of the facesheets hadexcellent adhesion to the SMC and all formed smooth class A surfaces.DSM944 contains 35% fiberglass and the same polyester resin and calciumcarbonate pigment as the aforementioned SCM sheets.

EXAMPLE 5

500 micron thick sheet of Belxoy® M 201 of Zytel 101 nylon/Arylon 401polyester/functionalized polyethylene ratio 55/32/13 and Bexloy® M 202of Zytel® 158/Arylon 401/functionalized polyethylene ratio 55/32/13 eachhaving a glass transition temperature of about 170° C. were used in theprocess of Example 4 but had no adhesion to any of the SMC sheets. SAN,ABS, and polycarbonates resins each having a glass transitiontemperature of less than 100° C. were likewise tested and failed becauseof their low Tg which caused these materials to stick to the mold faceand showed imperfections caused by glass fibers on the surface of thesheet.

EXAMPLE 6

The 500 micron sheets of Bexloy® M201, and Bexloy® M202 used in Example5 coated with 10 microns (dry weight) of the water borne size used inExample 1 on one side and baked 15 minutes at 100° C. to remove thesolvent. The sheets were trimmed and inserted into the 25.4-45.7 cm.plaque mold with 600 grams of green SMC (Budd Co. DSM 950 described inExample 1) with the size layer in contact with the green SMC. The moldwas closed compressing the charge and the facesheets at 8 MPa for 3minutes at a temperature of 155° C.

The resulting plaques were 0.32 cm. thick and the smooth Bexloy®facesheets formed a protective layer over the SMC plaque and had asmooth glassy surface free of imperfection. The adhesion of the sizedBexloy® facesheets was excellent.

EXAMPLE 7

A paint/size coated casting film was prepared as in Example 2 exceptthat a white PVF color coat with the following composition was usedinstead of the black.

    ______________________________________                                        Ingredient             Parts                                                  ______________________________________                                        White millbase         13                                                     PVF clear dispersion (described in                                                                   67                                                     Example 2)                                                                    methyl pyrrolidone     10                                                     propylene carbonate    10                                                     ______________________________________                                    

The white color coat has a P/B of 406/100 and a binder composition of98.8/1.2 PVF/AB acrylic dispersant.

The resulting paint/size coated casting film was transferred to alaminating operation where the paint was transferred from the castingfilm to a 325 micron sheet of Bexloy® M201 described in Example 5. Thecasting film was stripped away from the surface of the laminate, leavingthe white paint coat on the exterior of the nylon backing sheet.

30 microns (dry film build) of the water borne polyurethane size wasapplied to the Bexloy® side of the laminate and baked for 30 minutes at100° C. The resulting sized paint-coated laminate was returned to thelaminating operation where the laminate was laminated to a thin film ofBorg Warner Cycolac® L ABS resin.

The resulting facesheet was trimmed and inserted into the 25.4×45.7 cm.plaque mold with the PVF coating in contact with the mold face and 600grams of Budd Co. DSM 950 SMC described in Example 1 was placed in themold in contact with the facesheet. The mold was closed for 3 minutes at155° C. under a pressure of 10 MPa.

The resulting composite SMC plaque was glossy and smooth. When testedagainst automotive specifications, the composite showed the usefullnessof this process for producing automotive grade SMC parts.

EXAMPLE 8

250 micron and 625 micron thick sheets of Polyarylate D of Example 4were thermoformed by heating the facesheet to a temperature of about210° C. After the sheet was heated to this temperature, it was movedover a vacuum-former and a vacuum drawn to form the sheet into a25.4×45.7 cm. test plaque form.

The trimmed thermoform was then inserted into a 25.0×45.7 cm. plaquemold with 600 grams of Budd Co. DSM 950 SMC (described in Example 1) andthe mold closed for 3 minutes at 150° under a pressure of 7 MPa.

The resultant composite structures each have a smooth thermoplasticsurface that is easily cleanable.

We claim:
 1. A process for making a rigid composite structure with athermoplastic polymeric surface comprising the following steps:a.thermoforming a thermoplastic polymeric sheet into a three dimensionalthermoformed structure, said thermoplastic polymeric sheet having aprimary glass transition temperature at least 10° C. greater than atemperature of molding in step (e) below; b. opening a mold having anupper die and lower die with opposing molding surfaces cooperating todefine a mold cavity with one of the dies having a shape correspondingto the three dimensional thermoformed structure, c. placing thethermoformed structure of step (a) and a charge of a thermosetable sheetmolding compound comprising polyester resin, polymerizable monomers,filler pigments and glass fibers on the molding surface of one of thedies, d. closing the mold so that the dies compress the charge causingit to fill the mold cavity and come into adherence with the thermoformedstructure, e. molding the charge and thermoformed structure under heatand pressure to adhere the sheet molding compound to the thermoformedstructure and to cure the sheet molding compound, wherein heating of themold is at least 10° C. below the glass transition temperature of thethermoplastic polymeric sheet, and f. opening the dies and removing theresulting composite structure having the thermoformed structure firmlyadhered to the cured sheet molding compound.
 2. The process of claim 1in which the thermoplastic polymeric sheet of the resulting compositestructure is about 125-1000 microns thick, the sheet molding compound ofthe resulting composite structure is about 1500-7500 microns inthickness, the thermoplastic polymeric sheet has a primary glasstransition temperature that is at least 10° C. greater than the moldingtemperature in step (e), step (e) being carried out at a temperature ofabout 135°-160° C. and under a pressure of about 3-15 MPa.
 3. Theprocess of claim 2 in which the charge of sheet molding compound coversabout 40-80% of the surface of the molding surface of the die.
 4. Theprocess of claim 2 in which the thermoplastic polymeric sheet isthermoformed at a temperature of about 190°-235° C. and under a vacuumand using a pressure assist of up to 3 atmospheres.
 5. The process ofclaim 2 in which the thermoplastic polymeric sheet comprises apolyarylate.
 6. The process of claim 5 in which the polyarylatecomprises at least one dihydric phenol and at least one dicarboxylicacid.
 7. The process of claim 6 in which the polyarylate comprises thepolymerization product of 2,2-bis(4-hydroxyphenyl) propane and and anaromatic dicarboxylic acid selected from the group consisting ofisophthalic acid, terephthalic acid or mixtures thereof.
 8. The processof claim 7 in which the polyarylate contains an olefin polymer withepoxide functionality and comprises the polymerization product of thefollowing monomers:(a) about 0.5-15% by weight, based on the weight ofthe olefin polymer, of ##STR2## where R is H or alkyl group having 1-6carbon atoms, (b) about 45-99% by weight, based on the weight of theolefin polymer, of CH₂ ═CHR where R is H or lower alkyl group, and (c)about 0.1-40% by weight, based on the weight of the olefin polymer, ofCH₂ ═C(R¹)COOR² where R¹ is H or lower alkyl and R² is an alkyl grouphaving 1-8 carbon atoms.
 9. The process of claim 8 in which the monomersconsist of(a) glycidyl methacrylate, (b) ethylene and (c) butylacrylate.
 10. The process of claim 8 in which the polyarylate containsup to 15% by weight of a copolymer of at least one of styrene and alphamethyl styrene and at least one of acrylonitrile and methacrylonitrile.11. The process of claim 10 in which the copolymer consists essentiallyof styrene and acrylonitrile.
 12. The process of claim 1 in which thesheet molding compound contains greater than 30% by weight of glassfibers.
 13. The process of claim 1 in which the polyester resin consistsessentially of an acid terminated polyester of an alkylene glycol and analiphatic and aromatic dianhydride or acid and the monomers are styrene,alpha methyl styrene or mixtures thereof.
 14. The process of claim 13 inwhich the polyester consists essentially of propylene glycol,isophthalic acid and maleic anhydride and the monomer is styrene and thepolyester is reacted with magnesium
 15. The process of claim 14 in whichthe sheet molding compound contains up to 15% by weight of a low profileadditive comprising a high molecular weight thermoplastic resin.
 16. Theprocess of claim 2 in which the thermoplastic polymeric sheet is coatedwith at least one size layer, the size layer being selected from thegroup consisting of polyurethane, acrylonitrile/butadiene/styreneterpolymer, styrene/acrylonitrile polymer and polystyrene.
 17. Theprocess of claim 16 in which the thermoplastic polymeric sheet materialcomprises a polyamide modified with polyarylate or poly(2,6 dimethylphenylene oxide) and the size layer comprises a polyurethane.
 18. Theprocess of claim 16 in which the thermoplastic polymeric sheet comprisespolyether sulfanone.
 19. The process of claim 2 in which thethermoplastic polymeric sheet contains sufficient pigment to provide acomposite with a color.
 20. The process of claim 2 in which thethermoplastic polymeric sheet has a layer of a thermoplastic pigmentcontaining paint firmly bonded thereto on the side not in contact withthe SMC sheet and a layer of a glossy clear thermoplastic finish bondedto the paint layer; wherein a clear layer of a thermoplastic polymercoating composition is applied to a flexible polymeric carrier sheethaving a smooth glossy surface and drying said clear layer, applying apigmented layer of a thermoplastic polymer coating composition onto theclear layer drying said pigmented layer and then laminating with heatand pressure the flexible polymeric carrier sheet with the clear layerand pigmented layer to the thermoformable thermoplastic polymericmaterial resulting in the pigmented layer being adhered to thethermoformable polymeric material to form a laminate and removal of thecarrier sheet; the exterior surface of the clear layer substantiallyretains the glossy surface transferred to it from the polymeric carriersheet.
 21. The process of claim 20 in which the paint and the clearthermoplastic finish have a binder selected from the group consist ofpolyvinyl fluoride, polyvinylidene fluoride or a blend of polyvinylidenefluoride and polymethyl methacrylate or polyethyl methacrylate.
 22. Theprocess of claim 2 in which the thermoplastic polymeric sheet has alayer of a thermoplastic pigment containing paint firmly bonded theretoon the side not in contact with the sheet molding compound sheet;wherein a layer of a pigmented paint is applied to a flexible polymericcarrier sheet having a smooth glossy surface and drying said layer andthen laminating with heat and pressure the flexible polymeric carriersheet with a clear layer and pigmented layer to the thermoformablethermoplastic polymeric material resulting in the pigmented layer beingadhered to the thermoformable polymeric material to form a laminate andremoval of the carrier sheet; the exterior surface of the layer ofpigment containing paint substantially retains the glossy surfacetransferred to it from the polymeric carrier sheet.
 23. The process ofclaim 22 in which the paint has a binder selected from the group consistof polyvinyl fluoride, polyvinylidene fluoride or a blend ofpolyvinylidene fluoride and polymethyl methacrylate or polyethylmethacrylate.
 24. The process of claim 2 in which a thermoforming moldis used having at least two molding areas and at least two of thethermoformed structures are formed therein.
 25. The process of claim 2in which the composite structure is removed from the mold before beingfully cured and subsequently fully curing the composite structure byadditional heating or exposure to radiation.
 26. A process for making arigid composite structure with a thermoplastic polymeric surfacecomprising the following steps:a. opening a mold having an upper die andlower die with opposing molding surfaces cooperating to define a moldcavity, b. placing a thermoplastic polymeric sheet comprising apolyarylate having a primary glass transition temperature at least 10°C. greater than a temperature of molding in step (d) below and a chargeof sheet molding compound comprising polyester resin, polymerizablemonomers, filler pigments and fiber glass on the molding surface of oneof the dies, c. closing the mold so that the dies compress the chargecausing it to fill the mold cavity and come into adherence with thethermoplastic polymeric sheet, d. molding the charge and thermoplasticpolymeric sheet under heat and pressure to adhere the sheet moldingcompound to the thermoplastic polymeric sheet and cure the sheet moldingcompound; wherein heating of the mold is at least 10° C. below the glasstransition temperature of the thermoplastic polymeric sheet, and e.opening the dies and removing the resulting composite structure havingthe thermoplastic polymeric sheet firmly adhered to the cured sheetmolding compound.
 27. The process of claim 26 in which the thermoplasticpolymeric sheet is about 125-1000 microns thick, the sheet moldingcompound is about 1500-7500 microns in thickness, the thermoplasticpolymeric sheet has a primary glass transition temperature that is atleast 10° C. greater than the molding in step d.; said step d. beingcarried out at about 135°-160° C. and under a pressure of about 3-15MPa.